Cathode ray tube



ILM.

E RUSKA CATHODE RAY TUBE FiledV Sept. 16., 1936 l' 'fill l I.

Jan. l0, 1939.

Patented Jan. 10, 1939 ausser 2,143,581 CATHODE RAY TUBE Ernst Ituska, Berlin-Zehlendorf,

the firm Fernseh near Eerlin, Germany signor to Zehlendorf Application September In G Erma/Illy 6P 2 Claims.

The present invention relates to an especially simple method for fastening electrode systems in electron tubes, especially those involving secondary emission, and particularly multiplier tubes and electron ray tubes, for example those intended for image scanning and image composing as well as oscillograph work.

In the production of Braun tubes it is larly desirable that the electrode system be positioned against the neck of the tube in as simple a manner as possible and held rigid therein before the glass foot is fused together with the neck of the tube.

In accordance w'th the invention spread rings are provided at one or more places of the portions of the tube destined to receive the electrode system and to which rings the individual electrodes or an entire electrode system are fastened. The spread rings are preferably in the form of short, slotted, thin-walled cylinders. In order to hold any of the electrodes of the electrode system the cylinder is provided with a cross yoke which is fastened thereto at right angles e. g. by welding or riveting, or it may be bent out at right angles to the ray and tube axis as a portion of the spread ring. This cross yoke then serves for retaining the electrodes. However, erable to form the cross yoke itself as an electrode which is then connected with the spread ring.

The width of these bent-out lugs must be small at the bending point if the spread ring at this point is not to suffer in 'its resilient qualities. In order to impart sufficient stiffness to the electrodes as compared with the spread ring, two lugs may be bent out at points on the spread ring at points separated about apart, and` preferably in such fashion that the one lug aids in supporting the other in both axial directions. For this purpose the second lug is formed as a fork at its ends so as to maintain a free movability of both lugs with respect to each other in a plane perpendicutube axis (spread ring plane). I-Iowever one lug will suffice for fastening the anode diaphragm in a manner stiff enough to permit bending if it is supplementarily supported against the spread ring by means of a small support member.

Owing to the baking process to which the tube is subjected, the material used for the spread rings should preferably be a resilient material possessing great resistance to heat and softening, such as chromiuin-nickel, nickel-beryllium alloys; in addition, in most cases non-magnetic material must be used in making the spread rings. For

particu- Germany, as- Aktiengesellschaft,

Serial No. 101,172

(Cl. 25m-141) this purpose the alloy Contrazidberyllium is In cases Where a conducting, interior coating tube, the spread ring also teniber 24,

ATENT OFFiCE known commercially as particularly suited.

high or low ohmic is disposed onv the wall of the simultaneously serves the functionof making contact between the coatpotential. particularly one inasmuch as large surfaces are contact with adequate pressure.

scratching of the very sensitive inner electrode which latter is at the same positive brought into scraping or wall of the tube (producing danger of cracking in the case of glass tubes) may readily be obviated by introducing the spread ring in squeezed-together condition into the neck cial tools and then first allowing it to when correctly positioned so that it fits the wall of the tube.

by means of spe- 1 expand against For this purpose lboth ends of the ring may be provided with inwardly bent of which the spread ring to the inner wall of the ring may be squeezed its inside so as to be able readily to For this purpose obviously a slit must be available. Ihe respread ring may be such, the material of the tube (glass, a very positive and rigid In other better adhesion of the tube, the

Withwall thereof or the material of the spread ring may be roughened or provided with flutings running in the direction of the tube axis. The curvature of the spread ring is preferably less in the center than at the two ends, that the terminal curvature may the width of the tube so and for the reason be adapted to that when finally positioned it becomes uniformly pressed against the neck.

In case one spread ring is destined to carry an entire electrode system, the said system prior to insertion vided with inserted into the neck of the may be mounted on a glass socket prolead-ins, e. g. a press-foot, and then tube in a mechanically rigid manrier by means of special tools. The melting together of the neck of the tube and the glass foot may then be effected in a simple manner while insuring the exact coaxial positioning of the system with respect to the tube.

In the drawing:

Fig. 1 shows a spread ring according to the invention.

Fig. 2 is a top view of Fig. 1.

Fig. 3 is a spread ring which serves for an electrode system.

holding able to stiifen support arm i3.

rings it is tem, to adjust the respect to. each other.

e invention is obviously not limited to the foregoing examples. support the lug 3 in both spread ring electrodes may be inserted at various portions of the tube. This has ring and diaphragm 6 is fastened to the cross yoke, mainly thi ough the axial separation of their elecl0 by an insulating ring 1 threadably engaging over trodes may be produced by using the saine indisaid diaphragm ring, said rings being both providual electrodes except that they are inserted vided With threads and serving for holdin T the with diieient degrees of separatio accelerating system e two ends of the spread n lieu of one spread ring :or fastening eleclr ring 2 which form the slit are bent over to form trodes which extend lengthwise in the direction o lugs E as shown in Fig. 2 so that when the spread of the tube axis, as ior example the anode tube ring is squeezed together a good grip will be pro- 9, two or moie small or wire-shaped spi ead rings vided for the tool used. may also be used and disposed at both ends of Fig. 3 shows by way of example the use of the the electrodes or distributed along the length of 20 spread ring of the invention foi fastening an elect e entire elect trode system as used in a Braun tube intended It has been found to be preferable, when dealfor television reception purposes An anode diaing with a tubular electrode, to position a portion pi iagm 6 is positively centered upon a cross yoke of the electrode by means of a spread ring which 3, pieferably togethei with a. Wehnelt cylinder 9 is not applied to the Wall of t e tube but rather 5 the said yoke being, for example, fastened by spot to the inner side of the electrode. welding to the center of the spread ring 2 and I claim: perpendicular thereto y means of spread ring 1. In a cathode ray tube, electrode positioning t e entire system may thus be rigidly anchoied means comprising a split expansible metallic ring into the tube portion l without using any special adapted to t within and press against said tube, 30 device thereon However, as shown in Fig 3 e ends oi said iing adjacent the split therein he anode diaphragm t may be held in a hole being bent inwardly, oppositely disposed main lugs in the cross yoke by means of an vinsulating ormed integrally with said ring and extending threaded ring 7. The .control electrode 9 of the inwardly theiefron across and normal to the axis cathode which is fastened to the press foot is of tube, an auxiliary lug formed upon and screwed into the insulating threaded ring i and parallel to one of said main lugs, said auxiliary lug "d centered thereby with respect to the anode system and its main lug being adapted to t around and whereupon the press foot is fused together with mly position the OiJpOSely dispersed main lug t e neck of the tube. In this embodiment the against movement parallel to the axis of said tube, spread ring .2 effects contact between the coating and means disposed through said main lugs 40 l2 and the anode diaphragm adapted to receive an electrode to be supported Fig 4 shows the arrangement of a number of and xedly attached thereto. spread rings L?, 2', 2 whichserve for receiving in- 2 In a Cathde ray tube, SIQCFOCG DOSIlOnlHg dividuai electrodes, e. g. the Vcontrol electrode 9, means comprising a split, expansible, metallic ring the Vanode diaphragm S with the anode tube le, adapted to fit within and press against said tube, and the anode disk respectively. During the t e ends oi said ring adjacent the split therein fas ning of the anode diaphragm S together with @111g bent inwardly, Oppositely disposed main lugs the anode tube il) to the spread ring Z2 the proformed integrally with'said ring and extending ince ure may be such that the anode tube le is Wardly therefrom across and normal to the axis of centered by means of three bent over lugs not said tube, an auxiliary lug formed upon and shown with respect to a hole in the cross yoke parallel to one of said main lugs, said auxiliary through which the anode diaphragm and tube iug and its main lug being adapted to fit around 6 provided with external threads and flange is inand firmly position the oppos-tely disposed main serted from the screen side. The anode dialug against movement parallel to tie axis of said phragin S is then, together with the lugs of the u e, means disposed through said main lugs s anode tube l l drawn up tight by means of a adapted o receive an electiode to a and xedly attached thereto, an insulating memn the embodiment s own in the drawing the bei' attached to said electrode, and an additional aforesaid three parts are shown connected toelectrode supported by said insulating member. gether by spot welding 'In this case it is prefer- ERNST RUSKA. 

